INTRODUCTION written are likely to sin by anachronism Rare is the historian of philosophy who can tread Wrmly without falling into either trap Each of these errors can nullify the purpose of the enterprise The historian who is unconcerned by the philosophical problems that troubled past writers has not really understood how they themselves conducted their thinking The philosopher who ignores the historical background of past classics will gain no fresh light on the issues that concern us today, but merely present contemporary prejudices in fancy dress The two dangers threaten in diVerent proportions in diVerent areas of the history of philosophy In the area of metaphysics it is superWciality which is most to be guarded against: to someone without a personal interest in fundamental philosophical problems the systems of the great thinkers of the past will seem only quaint lunacy In political philosophy the great danger is anachronism: when we read Plato’s or Aristotle’s criticisms of democracy, we shall not make head or tail of them unless we know something about the institutions of ancient Athens In between metaphysics and political philosophy stand ethics and philosophy of mind: here both dangers threaten with roughly equal force I shall attempt in these volumes to be both a philosophical historian and a historical philosopher Multi-authored histories are sometimes structured chronologically and sometimes structured thematically I shall try to combine both approaches, oVering in each volume Wrst a chronological survey, and then a thematic treatment of particular philosophical topics of abiding importance The reader whose primary interest is historical will focus on the chronological survey, referring where necessary to the thematic sections for ampliWcation The reader who is more concerned with the philosophical issues will concentrate rather on the thematic sections of the volumes, referring back to the chronological surveys to place particular issues in context Thus in this Wrst volume I oVer in the Wrst part a conventional chronological tour from Pythagoras to Augustine, and in the second part a more detailed treatment of topics where I believe we have still much to learn from our predecessors in classical Greece and imperial Rome The topics of these thematic sections have been chosen partly with an eye to the development of the same themes in the volumes that are yet to come xx